Evaluation of the diagnostic value of transcranial electrical stimulation (TES) to assess neuronal functional integrity in horses.

Medical imaging allows for the visualization of spinal cord compression sites; however, it is impossible to assess the impact of visible stenotic sites on neuronal functioning, which is crucial information to formulate a correct prognosis and install targeted therapy. It is hypothesized that with the transcranial electrical stimulation (TES) technique, neurological impairment can be reliably diagnosed. Objective: To evaluate the ability of the TES technique to assess neuronal functional integrity in ataxic horses by recording TES-induced muscular evoked potentials (MEPs) in three different muscles and to structurally involve multiple ancillary diagnostic techniques, such as clinical neurological examination, plain radiography (RX) with ratio assessment, contrast myelography, and post-mortem gross and histopathological examination. Methods: Nine ataxic horses, showing combined fore and hindlimb ataxia (grades 2-4), were involved, together with 12 healthy horses. TES-induced MEPs were recorded bilaterally at the level of the trapezius (TR), the extensor carpi radialis (ECR), and tibialis cranialis (TC) muscles. Two Board-certified radiologists evaluated intra- and inter-sagittal diameter ratios on RX, reductions of dorsal contrast columns, and dural diameters (range skull-T1). Post-mortem gross pathological and segmental histopathological examination was also performed by a Board-certified pathologist. Results: TES-MEP latencies were significantly prolonged in both ECR and TC in all ataxic horses as opposed to the healthy horses. The TR showed a mixed pattern of normal and prolonged latency times. TES-MEP amplitudes were the least discriminative between healthy and ataxic horses. Youden's cutoff latencies for ataxic horses were 24.6 ms for the ECR and 45.5 ms for the TC (sensitivity and specificity of 100%). For healthy horses, maximum latency values were 22 and 37 ms, respectively. RX revealed spinal cord compression in 8 out of 9 involved ataxic horses with positive predictive values of 0-100%. All ataxic horses showed multi-segmental Wallerian degeneration. All pathological changes recorded in the white matter of the spinal cord were widely dispersed across all cervical segments, whereas gray matter damage was more localized at the specific segmental level. Conclusion: TES-MEP latencies are highly sensitive to detect impairment of spinal cord motor functions for mild-to-severe ataxia (grades 2-4).

Diagnostic accuracy of plain radiography to identify synovial penetration in horses with traumatic limb wounds.

BACKGROUND: The diagnostic value of plain radiography for diagnosing synovial penetration in limb wounds near synovial structures has not been determined. OBJECTIVES: To assess diagnostic accuracy of plain radiography to identify synovial penetration in horses with traumatic limb wounds. STUDY DESIGN: Retrospective case study. METHODS: Case records of horses presented to the Faculty of Veterinary Medicine of Ghent University (2011-2021) with limb wounds near synovial structures were categorised in groups with and without synovial penetration using results of synovial fluid analysis and surgical findings. Plain radiographic images were evaluated retrospectively. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for the total study sample and for the cases with and without use of a metallic probe in the wound during radiographic evaluation. RESULTS: Based on the total sample of 141 horses with synovial penetration and 75 cases without synovial involvement, plain radiography presented a sensitivity of 61% (95% CI: 52%-69%), a specificity of 81% (95% CI: 70%-89%), a PPV of 86% (95% CI: 79%-90%) and a NPV of 53% (95% CI: 46%-58%). With the use of a metallic probe, a sensitivity of 54% (95% Cl: 39%-69%), a specificity of 88% (95% Cl: 64%-99%), a PPV of 93% (95% Cl: 78%-98%) and a NPV of 41% (95% Cl: 32%-49%) were obtained. MAIN LIMITATIONS: Sample size did not allow comparing different synovial structures. Results can be influenced by individual case characteristics. CONCLUSIONS: If findings of a series of plain radiographs suggest synovial penetration in horses with a wound near a synovial cavity, then synovial penetration is likely, but the absence of plain radiographic findings does not rule out synovial penetration. The use of a metallic probe during radiography may be helpful. However, plain radiography should be interpreted cautiously, and clinical decision making should also include other techniques.

CONTEXTO: O valor diagnóstico de radiografias planas para diagnosticar penetração sinovial em feridas nos membros próximas a estruturas sinoviais não é determinado. OBJETIVOS: Investigar a acurácia diagnóstica de radiografias planas para identificar penetração sinovial em cavalos com feridas traumáticas nos membros. DELINEAMENTO DO ESTUDO: Estudo de casos retrospectivos. MÉTODOS: Prontuários médicos de equinos hospitalizados na Faculdade de Medicina Veterinária da Universidade de Guent (2011-2021) com feridas nos membros próximas a estruturas sinoviais foram categorizados em grupos com e sem penetração sinovial utilizando resultados de citologia e achados cirúrgicos. Radiografias planas foram analisadas retrospectivamente. Sensibilidade, especificidade, valor preditivo negativo (VPN) e positivo (VPP) foram calculados para todos os animais incluídos, e para os casos com e sem o uso de uma probe metálica na radiografia. RESULTADOS: Baseado no número total de 141 cavalos com penetração sinovial e 75 cavalos sem envolvimento sinovial, radiografia plana apresentou uma sensibilidade de 61% (95% IC: 52%-69%), especificidade de 81% (95% IC: 70%-89%), VPP de 86% (95% IC: 79%-90%) e VPN de 53% (95% IC: 46%-58%). Com o uso da probe metálica, a sensibilidade foi de 54% (95% IC: 39%-69%), especificidade de 88% (95% IC: 64%-99%), VPP de 93% (95% IC: 78%-98%) e VPN de 41% (95% IC: 32%-49%). PRINCIPAIS LIMITAÇÕES: O pequeno número de animais não possibilitou a comparação entre diferentes tipos de estruturas sinoviais. Os resultados podem ter sido influenciados por características individuais. CONCLUSÕES: Se os achados de radiografia plana sugerem penetração sinovial em equinos com feridas no membro próximas a estruturas sinoviais, penetração sinovial é provável, mas a ausência de achados radiográficos indicativos não excluem a presença de penetração sinovial. O uso de uma probe metálica pode ser útil. Contudo, radiografias planas devem ser interpretadas cautelosamente, e a decisão clínica deve ser baseada em uma combinação com outras modalidades.

Single energy metal artifact reduction performs better than virtual monoenergetic dual-energy reconstruction in CT of the equine proximal phalanx.

Metal artifacts in CT negatively impact the evaluation of surgical implants and the surrounding tissues. The aim of this prospective experimental study was to evaluate the ability of a single energy metal artifact reduction (SEMAR™, Canon) algorithm and virtual monoenergetic (VM) dual-energy CT (DECT) scanning techniques to reduce metal artifacts from stainless steel screws surgically inserted into the equine proximal phalanx. Seven acquisitions of 18 cadaver limbs were performed on a Canon Aquilion One Vision CT scanner (Helical +SEMAR, Volume +SEMAR, Standard Helical, Standard Volume and VM DECT at 135, 120, and 105 keV) and reconstructed in a bone kernel. Blinded subjective evaluation performed by three observers indicated a significant effect of acquisition in both adjacent tissues (P < 0.001) and distant tissues (P < 0.001) and the best metal artifact reduction was seen with Helical +SEMAR and Volume +SEMAR. The subjective overall preference of CT acquisition type was (1) Helical +SEMAR, (2) Volume +SEMAR, (3) VM DECT 135 keV, (4) VM DECT 120 keV, (5) VM DECT 105 keV, (6) Standard Helical, (7) Standard Volume (P < 0.001). Unblinded objective evaluation performed by one observer showed that VM DECT 120 keV, Helical +SEMAR, and Volume +SEMAR performed similarly and were objectively the best at reducing blooming artifact. Overall, the best metal artifact reduction was obtained with SEMAR, followed by VM DECT. However, VM DECT performance varies with energy level and was associated with decreased image quality in distant tissues and artifactual overcorrection of metal artifacts at high energy levels.

Post-mortem feasibility of dual-energy computed tomography in the detection of bone edema-like lesions in the equine foot: a proof of concept.

Introduction: In this proof-of-concept study, the post-mortem feasibility of dual-energy computed tomography (DECT) in the detection of bone edema-like lesions in the equine foot is described in agreement with the gold standard imaging technique, which is magnetic resonance imaging (MRI). Methods: A total of five equine cadaver feet were studied, of which two were pathological and three were within normal limits and served as references. A low-field MRI of each foot was performed, followed by a DECT acquisition. Multiplanar reformations of DECT virtual non-calcium images were compared with MRI for the detection of bone edema-like lesions. A gross post-mortem was performed, and histopathologic samples were obtained of the navicular and/or distal phalanx of the two feet selected based on pathology and one reference foot. Results: On DECT virtual non-calcium imaging, the two pathological feet showed diffuse increased attenuation corresponding with bone edema-like lesions, whereas the three reference feet were considered normal. These findings were in agreement with the findings on the MRI. Histopathology of the two pathologic feet showed abnormalities in line with bone edema-like lesions. Histopathology of the reference foot was normal. Conclusion: DECT virtual non-calcium imaging can be a valuable diagnostic tool in the diagnosis of bone edema-like lesions in the equine foot. Further examination of DECT in equine diagnostic imaging is warranted in a larger cohort, different locations, and alive animals.

Diagnosis and Surgical Treatment of Idiopathic Primary Sino-Nasal Obstruction in Miniature Horse Breeds: Long-Term Follow-Up of Seven Cases.

Idiopathic sino-nasal obstruction resulting in retention of large amounts of liquid in the paranasal sinus compartments was diagnosed in seven young (2. 2 ± 0.7 years) miniature-breed horses based on clinical, endoscopic, radiographic, and CT scan examinations. The most prevalent clinical signs included decreased or no airflow from the nostril(s) (7/7) and nasal discharge (6/7). The problem presented bilaterally in six of seven cases. An alternative sino-nasal communication was created through bone flap osteotomy surgery and perforation of the ventromedial floor of the dorsal conchae in all cases, followed by fixation of silicone irrigation tubes/Foley catheters in six of seven cases to keep the newly created ostium patent. This resulted in long-term resolution of the problem with good cosmetic appearance in all animals following a median period of 19 months. Premature loss of fixed tubes was reported in three cases.

Cadaveric comparison of the accuracy of ultrasound-guided versus 'blind' perineural injection of the tibial nerve in horses.

During diagnostic evaluation of hindlimb lameness in horses the tibial nerve block is traditionally performed based on anatomical reference points, but it can be difficult to achieve effective local anaesthesia using this blind technique. Ultrasound (US)-guided injection could increase the accuracy of injection. The aim of this study was to compare the accuracy of both techniques. Twenty-one paired sets of cadaver hindlimbs were injected with 1 mL methylene blue using the blind or US-guided technique. There was no significant difference in stain width and length and in coloured nerve length between techniques. However, the successful rate of nerve staining was 85.7% and 47.6% for the US-guided and blind technique, respectively (P = 0.02; odds ratio 6.6; 95% confidence interval, 1.5-29.4). This study suggests that the US-guided technique is more accurate than the blind technique. However, in the treated sample, a single US-guided injection did not consistently result in nerve staining.

Accuracy of transcranial magnetic stimulation and a Bayesian latent class model for diagnosis of spinal cord dysfunction in horses.

BACKGROUND: Spinal cord dysfunction/compression and ataxia are common in horses. Presumptive diagnosis is most commonly based on neurological examination and cervical radiography, but the interest into the diagnostic value of transcranial magnetic stimulation (TMS) with recording of magnetic motor evoked potentials has increased. The problem for the evaluation of diagnostic tests for spinal cord dysfunction is the absence of a gold standard in the living animal. OBJECTIVES: To compare diagnostic accuracy of TMS, cervical radiography, and neurological examination. ANIMALS: One hundred seventy-four horses admitted at the clinic for neurological examination. METHODS: Retrospective comparison of neurological examination, cervical radiography, and different TMS criteria, using Bayesian latent class modeling to account for the absence of a gold standard. RESULTS: The Bayesian estimate of the prevalence (95% CI) of spinal cord dysfunction was 58.1 (48.3%-68.3%). Sensitivity and specificity of neurological examination were 97.6 (91.4%-99.9%) and 74.7 (61.0%-96.3%), for radiography they were 43.0 (32.3%-54.6%) and 77.3 (67.1%-86.1%), respectively. Transcranial magnetic stimulation reached a sensitivity and specificity of 87.5 (68.2%-99.2%) and 97.4 (90.4%-99.9%). For TMS, the highest accuracy was obtained using the minimum latency time for the pelvic limbs (Youden's index = 0.85). In all evaluated models, cervical radiography performed poorest. CLINICAL RELEVANCE: Transcranial magnetic stimulation-magnetic motor evoked potential (TMS-MMEP) was the best test to diagnose spinal cord disease, the neurological examination was the second best, but the accuracy of cervical radiography was low. Selecting animals based on neurological examination (highest sensitivity) and confirming disease by TMS-MMEP (highest specificity) would currently be the optimal diagnostic strategy.

Determination of magnetic motor evoked potential latency time cutoff values for detection of spinal cord dysfunction in horses.

BACKGROUND: Transcranial magnetic stimulation (TMS) and recording of magnetic motor evoked potentials (MMEP) can detect neurological dysfunction in horses but cutoff values based on confirmed spinal cord dysfunction are lacking. OBJECTIVES: To determine latency time cutoff for neurological dysfunction. ANIMALS: Five control horses and 17 horses with proprioceptive ataxia. METHODS: Case-control study with receiver operating characteristic curve analysis, based on diagnostic imaging, TMS, and histopathological findings. Horses were included if all 3 examinations were performed. RESULTS: Diagnostic imaging and histopathology did not show abnormalities in the control group but confirmed spinal cord compression in 14 of 17 ataxic horses. In the remaining 3 horses, histopathological lesions were mild to severe, but diagnostic imaging did not confirm spinal cord compression. In control horses, latency time values of thoracic and pelvic limbs were significantly lower than in ataxic horses (20 ± 1 vs 34 ± 16 milliseconds, P = .05; and 39 ± 1 vs 78 ± 26 milliseconds, P = .004). Optimal cutoff values to detect spinal cord dysfunction were 22 milliseconds (sensitivity [95% CI interval], 88% [73%-100%]; specificity, 100% [100%-100%]) in thoracic and 40 milliseconds (sensitivity, 94% [83%-100%]; specificity, 100% [100%-100%]) in pelvic limbs. To detect spinal cord dysfunction caused by compression, the optimal cutoff for thoracic limbs remained 22 milliseconds, while it increased to 43 milliseconds in pelvic limbs (sensitivity, 100% [100%-100%]; specificity, 100% [100%-100%] for thoracic and pelvic limbs). CONCLUSIONS AND CLINICAL IMPORTANCE: Magnetic motor evoked potential analysis using these cutoff values is a promising diagnostic tool for spinal cord dysfunction diagnosis in horses.

Comparison of cross-sectional anatomy and computed tomography of the tarsus in horses.

OBJECTIVE: To compare computed tomography (CT) images of equine tarsi with cross-sectional anatomic slices and evaluate the potential of CT for imaging pathological tarsal changes in horses. SAMPLE: 6 anatomically normal equine cadaveric hind limbs and 4 tarsi with pathological changes. PROCEDURES: Precontrast CT was performed on 3 equine tarsi; sagittal and dorsal reconstructions were made. In all limbs, postcontrast CT was performed after intra-articular contrast medium injection of the tarsocrural, centrodistal, and tarsometatarsal joints. Images were matched with corresponding anatomic slices. Four tarsi with pathological changes underwent CT examination. RESULTS: The tibia, talus, calcaneus, and central, fused first and second, third, and fourth tarsal bones were clearly visualized as well as the long digital extensor, superficial digital flexor, lateral digital flexor (with tarsal flexor retinaculum), gastrocnemius, peroneus tertius, and tibialis cranialis tendons and the long plantar ligament. The lateral digital extensor, medial digital flexor, split peroneus tertius, and tibialis cranialis tendons and collateral ligaments could be located but not always clearly identified. Some small tarsal ligaments were identifiable, including plantar, medial, interosseus, and lateral talocalcaneal ligaments; interosseus talocentral, centrodistal, and tarsometatarsal ligaments; proximal and distal plantar ligaments; and talometatarsal ligament. Parts of the articular cartilage could be assessed on postcontrast images. Lesions were detected in the 4 tarsi with pathological changes. CONCLUSIONS AND CLINICAL RELEVANCE: CT of the tarsus is recommended when radiography and ultrasonography are inconclusive and during preoperative planning for treatment of complex fractures. Images from this study can serve as a CT reference, and CT of pathological changes was useful.

Computed tomographic anatomy of the equine stifle joint.

OBJECTIVE: To provide a detailed computed tomography (CT) reference of the anatomically normal equine stifle joint. Sample-16 hind limbs from 8 equine cadavers; no horses had evidence of orthopedic disease of the stifle joints. PROCEDURES: CT of the stifle joint was performed on 8 hind limbs. In all limbs, CT was also performed after intra-articular injection of 60 mL of contrast material (150 mg of iodine/mL) in the lateral and medial compartments of the femorotibial joint and 80 mL of contrast material in the femoropatellar joint (CT arthrography). Reformatted CT images in the transverse, parasagittal, and dorsal plane were matched with corresponding anatomic slices of the 8 remaining limbs. RESULTS: The femur, tibia, and patella were clearly visible. The patellar ligaments, common origin of the tendinous portions of the long digital extensor muscle and peroneus tertius muscle, collateral ligaments, tendinous portion of the popliteus muscle, and cranial and caudal cruciate ligaments could also be consistently evaluated. The cruciate ligaments and the meniscotibial ligaments could be completely assessed in the arthrogram sequences. Margins of the meniscofemoral ligament and the lateral and medial femoropatellar ligaments were difficult to visualize on the precontrast and postcontrast images. CONCLUSIONS AND CLINICAL RELEVANCE: CT and CT arthrography were used to accurately identify and characterize osseous and soft tissue structures of the equine stifle joint. This technique may be of value when results from other diagnostic imaging techniques are inconclusive. The images provided will serve as a CT reference for the equine stifle joint.

Ultrasonographic findings in 100 horses with tarsal region disorders.

Ultrasonographic findings from 100 horses (103 joints) diagnosed with tarsal region pathology are described. Results of standard orthopaedic, radiographic and ultrasonographic examination of the tarsal region were analysed retrospectively. Periarticular swelling and/or synovial effusion was present in 100% of the joints, a wound was observed in 14.5% and 76.7% of the horses that were lame. Abnormalities were detected in 69.7% of joints using radiography and in 100% with ultrasonography. Our results show that the main disease process can affect all aspects of the tarsus. The most common ultrasonographic findings were synovitis of the tarso-crural joint (n=52) at the dorsal aspect, collateral ligament injury (n=23) at the lateral/medial aspect, and superficial digital flexor tendon injury (n=15) at the plantar aspect. Multiple ultrasonographic abnormalities were detected in 60 joints (58.3%) indicating that a complete and systematic ultrasonographic examination is mandatory when investigating the tarsal region.

Diagnostic imaging of the equine tarsal region using radiography and ultrasonography. Part 1: the soft tissues.

The equine tarsus is the most commonly affected hindlimb region associated with lameness. Diagnostic imaging is routinely applied but because of its complexity, being composed of 10 multifaceted bones and different joints, multiple ligaments, tendons and bursae, imaging this region can be a challenge. This is the first part of a two-part review of the structures and disorders of the equine tarsus. It describes the principal disorders affecting the soft tissues of the tarsal region and addresses some of the technical aspects in taking radiographic, ultrasonographic and scintigraphic images of the different soft tissue lesions. Where applicable, comments on the diagnostic use of contrast radiography, arthroscopy and tenoscopy are made. In current clinical practice a combination of radiography and ultrasonography is still most frequently used to arrive at a diagnosis.

Diagnostic imaging of the equine tarsal region using radiography and ultrasonography. Part 2: bony disorders.

This is the second part of a two-part review of the structures and disorders of the equine tarsus. In this part the bones of the tarsal region are considered and the technical aspects of taking radiographic, ultrasonographic and scintigraphic images of the different lesions are addressed. The diagnostic use of arthroscopy, computed tomography and magnetic resonance are discussed. In current clinical practice the most frequently used combination to arrive at a diagnosis is still radiography and ultrasonography.

Quality of life and health status in adults with congenital heart disease: a direct comparison with healthy counterparts.

INTRODUCTION: Despite having increased life expectancy, patients with congenital heart disease are sometimes presumed to have a diminished quality of life. This study therefore assessed the quality of life and perceived health of adults with congenital heart disease and compared these two measures with those reported by healthy control subjects. METHODS: Using a comparative study design, we examined quality of life and perceived health in 404 patients who were matched for age, sex, educational level, and employment status with 404 healthy counterparts. Quality of life was measured using a linear analog scale and the Satisfaction with Life Scale. Problems and concerns relevant to patients' quality of life were assessed by the Congenital Heart Disease-TNO-AZL Adult Quality of Life scale. Perceived health was also assessed with a linear analog scale. RESULTS: Patients perceived their quality of life (median linear analog scale score 80; median Satisfaction with Life Scale score 28) and health status to be good (median linear analog scale 80). Quality of life was significantly better in patients with congenital heart disease than in healthy peers, with a mean standardized difference of 0.22 on the linear analog scale and 0.34 on the Satisfaction with Life Scale. No group difference was found for perceived health. Problems and concerns in adults with congenital heart disease overlapped to a large extent with those identified by control subjects. Patients reported significantly higher distress scores for 16 of 77 items, whereas control subjects perceived more distress for 20 items. CONCLUSION: Adults with congenital heart disease perceived their quality of life to be better than did their healthy counterparts. This finding refutes the presumed lower quality of life in patients with cardiac anomalies.

Individual quality of life in adults with congenital heart disease: a paradigm shift.

AIMS: During the last decade, a paradigm shift has emerged in the measurement of quality of life, from the use of standard questionnaires towards a more individualized approach. Therefore, this study examined individual quality of life in adults with congenital heart disease and explored potential differences with those reported by matched, healthy control subjects. METHODS AND RESULTS: We examined 579 adults with congenital heart disease. A subsample of 514 of these patients was matched for age, gender, educational level, and employment status with 446 healthy counterparts. Individual quality of life was assessed using the Schedule for the Evaluation of Individual Quality of Life-Direct Weighting (SEIQoL-DW). Twelve domains affecting patients' quality of life were identified. Family, job/education, friends, health, and leisure time were the most prominent quality of life domains. Significantly fewer patients than control subjects considered financial means and material well-being and future to be important determinants of quality of life. CONCLUSION: Assessment of quality of life in adults with congenital heart disease that focusses on the individual is appropriate for obtaining in-depth information on issues relevant for patients' quality of life. This represents a paradigm shift in the measurement of this concept.